Given two binary trees, write a function to check if they are the same or not.
Two binary trees are considered the same if they are structurally identical and the nodes have the same value.
Example 1:
Input: 1 1
/ \ /
2 3 2 3
[1,2,3], [1,2,3]
Output: true
Example 2:
Input: 1 1
/
2 2
[1,2], [1,null,2]
Output: false
Example 3:
Input: 1 1
/ \ /
2 1 1 2
[1,2,1], [1,1,2]
Output: false
解法
用递归的方法,首先判断p,q的val是否相同,然后分别判断他们的左右子节点是否相同
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
public boolean isSameTree(TreeNode p, TreeNode q) {
if(p==null&&q==null) return true;
if(p==null||q==null) return false;
if(p.val!=q.val) return false;
return isSameTree(p.left,q.left)&&isSameTree(p.right,q.right);
}
}